This research aims to increase understanding of psychosocial factors involved in human fertility control and to develop predictive indicators of success or failure in contraceptive planning. It investigates the motivation and personality of successful and unsuccessful contraceptors and their sexual attitudes and behavior,$ particularly attitudes toward family planning and experiences with contraception. This long-term longitudinal study involves random selection, interviewing, and administration of several behavioral, personality, and attitude measures to incoming intake patients at family planning clinics. Careful follow-up procedures have been developed to specify the criteria of contraceptive failure or success, and a three-year follow-up period should assure the stability of the criterion classification and maximize predictive validity. The project includes two additional phases: (1) intensive reinterviews with approximately 100 success and failure cases, incorporating new measures of factors which influenced the outcome of their contraceptive program, thus providing both in-depth descriptive and retrospective predictive analyses of birth-planning success; (2) an intensive study of teenagers' sexual and contraceptive socialization experiences, beginning with development of new assessment items, and then administering them to consecutive teenage intake patients in a similar longitudinal predictive study. BIBLIOGRAPHIC REFERENCES: Mindick, B., Oskamp, S., & Berger, D.E. Prediction of success or failure in birth planning: An approach to prevention of individual and family stress. American Journal of Community Psychology, 1977, in press. Mindick, B. Attitudes toward population issues. In S. Oskamp, Attitudes and Opinions. Englewood Cliffs, N.J.: Prentice-Hall, 1977, in press.